With the arrival of the Primogenitors, the Electoral War for Itogami Islandplungesfurther into chaos.Shio and Yuiri head to the island intending touse TwelthPrimogenitor, Avrora, to put an end to the conflict, only to comeface to face withSecond Primogenitor, Fallgazer.While Yukina rushes to theisland to save the three,elsewhere Kojou is suddenly overcome byinexplicable hunger and thirst, which isapparently tied to the Beast Vassalsthat resonate with the Primogenitors.Just whatwill Kojou have to do toregain his strength and stop the Beast Vassals' rampage?